The Biostatistics Core will play a pivotal role in the Northwest Prostate Cancer SPORE, interacting with virtually every project and Core. The defining goal of the Biostatistics Core will be to assist investigators in formulating studies that can feasibly address the questions of scientific interest, are amenable to statistical analysis, and will ultimately yield statistically valid and interpretable results. This Core will link study design, data collection, measurement, and analysis to the critical hypotheses and questions of the Northwest Prostate Cancer SPORE through the following Specific Aims: 1. Design: Define study hypotheses, study populations and experimental parameters to answer the research questions of interest, reduce systematic bias and ensure a high likelihood of detection of biologically meaningful effects. 2. Analysis: Identify and implement quantitative methods to address the scientific questions of interest and provide valid statistical inferences about the evidence supporting the various study hypotheses. To implement analyses of genomic expression data, the Biostatistics Core will utilize a software system for analysis of genomic expression data, currently under development at the Fred Hutchinson Cancer Research Center. This system will provide researchers on the SPORE with a user-friendly interface to a variety of standard as well as novel computational algorithms for the analysis of expression data. The Biostatistics Core will work closely with the Informatics and Gene Expression Core to define the microarray database for the array expression data generated by the proposed SPORE, and to select procedures for data normalization and quality control. The Biostatistics Core will also work with the Clinical Research Core to define the structure of a new clinical database, to design clinical trials of new treatment strategies and to design clinical validation studies for confirming the importance of genes discovered through SPORE projects.